In order to ascertain how the adhesive system differs in normal and malignant cells, we must first, fully understand how normal cells attach and second, compare the chemical components of the adhesion system in different types of normal cells and their malignant counterparts. Our studies will be carried out using normal and virus-transformed baby hamster kidney cells. We plan a multidisciplinary approach to the problem combining biochemical techniques with an ultrastructural analysis of attached and nonattached cells under various conditions. We shall attempt to isolate, identify, and characterize, the cell membrane/surface components involved in adhesion; to determine what ultrastructural and biochemical changes occur at the cell membrane/surface when suspended cells attach; and, to determine to what extent the processes of initial cell attachment and the increase in strength of cell attachment are similar. In addition we propose some preliminary experiments on cell adhesion related to the immune response.